2025-01-16 v. 8.1.2: added "967. Numbers With Same Consecutive Differences"

Author: fartem

README.md

@@ -647,6 +647,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 950. Reveal Cards In Increasing Order                            | [Link](https://leetcode.com/problems/reveal-cards-in-increasing-order/)                            | [Link](./lib/medium/950_reveal_cards_in_increasing_order.rb)                            | [Link](./test/medium/test_950_reveal_cards_in_increasing_order.rb)                            |
 | 951. Flip Equivalent Binary Trees                                | [Link](https://leetcode.com/problems/flip-equivalent-binary-trees/)                                | [Link](./lib/medium/951_flip_equivalent_binary_trees.rb)                                | [Link](./test/medium/test_951_flip_equivalent_binary_trees.rb)                                |
 | 958. Check Completeness of a Binary Tree                         | [Link](https://leetcode.com/problems/check-completeness-of-a-binary-tree/)                         | [Link](./lib/medium/958_check_completeness_of_a_binary_tree.rb)                         | [Link](./test/medium/test_958_check_completeness_of_a_binary_tree.rb)                         |
+| 967. Numbers With Same Consecutive Differences                   | [Link](https://leetcode.com/problems/numbers-with-same-consecutive-differences/)                   | [Link](./lib/medium/967_numbers_with_same_consecutive_differences.rb)                   | [Link](./test/medium/test_967_numbers_with_same_consecutive_differences.rb)                   |
 | 1400. Construct K Palindrome Strings                             | [Link](https://leetcode.com/problems/construct-k-palindrome-strings/)                              | [Link](./lib/medium/1400_construct_k_palindrome_strings.rb)                             | [Link](./test/medium/test_1400_construct_k_palindrome_strings.rb)                             |
 | 2116. Check if a Parentheses String Can Be Valid                 | [Link](https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/)                  | [Link](./lib/medium/2116_check_if_a_parentheses_string_can_be_valid.rb)                 | [Link](./test/medium/test_2116_check_if_a_parentheses_string_can_be_valid.rb)                 |
 | 2425. Bitwise XOR of All Pairings                                | [Link](https://leetcode.com/problems/bitwise-xor-of-all-pairings/)                                 | [Link](./lib/medium/2425_bitwise_xor_of_all_pairings.rb)                                | [Link](./test/medium/test_2425_bitwise_xor_of_all_pairings.rb)                                |

leetcode-ruby.gemspec

@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '8.1.1'
+  s.version = '8.1.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/967_numbers_with_same_consecutive_differences.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/numbers-with-same-consecutive-differences/
+# @param {Integer} n
+# @param {Integer} k
+# @return {Integer[]}
+def nums_same_consec_diff(n, k)
+  return (0..9).to_a if n == 1
+
+  nums = []
+  (1..9).each { |num| dfs_for_consec_diff(n - 1, num, k, nums) }
+
+  nums
+end
+
+private
+
+# @param {Integer} n
+# @param {Integer} k
+# @param {Integer[]} nums
+# @return {Void}
+def dfs_for_consec_diff(n, num, k, nums)
+  return nums.push(num) if n.zero?
+
+  next_digits = []
+  tail = num % 10
+
+  next_digits << tail + k unless k.zero?
+  next_digits << tail - k
+
+  next_digits.each do |next_digit|
+    next unless (0..9).include?(next_digit)
+
+    new_num = num * 10 + next_digit
+
+    dfs_for_consec_diff(n - 1, new_num, k, nums)
+  end
+end

test/medium/test_967_numbers_with_same_consecutive_differences.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/967_numbers_with_same_consecutive_differences'
+require 'minitest/autorun'
+
+class NumbersWithSameConsecutiveDifferencesTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      [181, 292, 707, 818, 929],
+      nums_same_consec_diff(3, 7)
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      [12, 10, 23, 21, 34, 32, 45, 43, 56, 54, 67, 65, 78, 76, 89, 87, 98],
+      nums_same_consec_diff(2, 1)
+    )
+  end
+end